Atlantic Seashore Field Guide: Florida to Canada

By J. Duane Sept

A photographic guide to the common plants and animals that inhabit the intertidal zone--the area covered by water at high tide and exposed during low tide--on the Atlantic coast from Cape Canaveral, Florida, to Cape Breton, Canada.

• Language: English
• Publisher: RowmanLittlefield
• Release date: Mar 1, 2016
• ISBN: 9780811763486

Book preview

INTRODUCTION

The Western Atlantic is well known for its diverse intertidal marine life. Thanks to a combination of wave exposure, shoreline type, and plentiful food, a rich abundance of animal and plant life can be found along the intertidal zone—the narrow strip of land that lies between the highest and lowest tide lines. Intertidal sites are best viewed when the tide reaches its lower levels.

TIDES

Tides are caused by the gravitational effects of the moon and sun acting upon the world’s oceans. The moon’s influence is stronger because of its proximity to earth. High tides occur when the moon is closest to the ocean, and the water level rises in response to the gravitational pull of the moon. When both the sun and moon are in the same orientation toward earth, the gravitational pull is greatest on the nearest oceans. When a low tide occurs at one side of earth, the opposite side experiences a high tide to compensate for the change in water level.

In the northern portion of the Western Atlantic, the tides are renowned for their high fluctuations. In Minas Basin, Nova Scotia, the height of the tide fluctuation can reach an incredible 53' (16 m). In Pensacola, Florida, however, the tides reach a maximum height of 2.0' (0.6 m) and a minimum height of -1.0' (-0.3 m)—a maximum fluctuation of 3' (1 m).

INTERTIDAL HABITATS

Several types of seashore may be found along our beaches. Each of these habitats is home to species whose physical features are specialized for that environment. Our shorelines have several intertidal zones, each inhabited by a particular combination of creatures and plant life. These zones are (from top to bottom) the spray zone, high intertidal zone, middle intertidal zone and low intertidal zone. Some species may be found in more than one type of habitat or intertidal zone.

ROCKY SHORES

Rocky beaches can contain a wide variety of creatures, including various anemones, limpets, chitons, and tunicates. While tidal zones are present in all tidal areas, they are most evident on rocky shorelines.

SANDY SHORES

Sandy shores are often found on exposed beaches; however, they may also be found in sheltered locations such as in bays. Creatures found on sandy shores will only be found in either exposed or sheltered sites but not both. Marine life forms that are found on sandy beaches include the Atlantic surfclam (p. 171), Carolinian ghost shrimp (p. 220), and iridescent sandworm (p. 36).

MUDDY SHORES

Muddy shores are typically found in sheltered sites such as in lagoons. Creatures found on muddy beaches include the softshell-clam (p. 190), eastern oyster (p. 155), and eastern mud snail (p. 117).

INTERTIDAL ETIQUETTE

The marine lifeforms that inhabit our shores are fragile, so please ensure your visit is a positive one for the creatures you have come to enjoy. Be careful where you step, and replace any rocks that you turn over. Creatures that require a moist or wet environment can dry out quickly when exposed to sunlight. When you leave, take care to pack out everything you brought with you. This will help preserve the seashore environment for other visitors as well as for the marine residents.

HARVESTING SHELLFISH

One of the many ways to enjoy the seashore is to harvest shellfish. If you plan to do so, ensure that you have the necessary license, and check for local restrictions and limits. Local areas are sometimes closed to harvesting because of pollution or algal blooms such as red tide.

RED TIDE

During the warmer months of the year, tiny algae reproduce rapidly (algal bloom). Each of these algae can contain tiny amounts of toxins, which are then concentrated in the body tissues of various filter-feeding organisms, including oysters, clams, mussels, scallops, and more. Once the algae die, the filter-feeders begin to rid themselves of the toxins naturally, which takes as little as four weeks, although it can take as long as two years for some species. Algal blooms can produce a poison (saxitoxin) that is 10,000 times more toxic than cyanide. So if you eat a tiny amount of shellfish that have ingested these toxins, you can become seriously or even fatally ill with paralytic shellfish poisoning (PSP). Cooking does not remove this toxin. To inform the public, government authorities regularly monitor shellfish for toxin levels, and affected areas are closed to shellfish harvesting. This information is available at various sites on the web or by making a phone call.

PSP (RED TIDE) HOTLINES

Worldwide

www.issha.org/Welcome-to-ISSHA/Harmful-Algae-Links/General-Information#list-state

Canada

www.dfo-mpo.gc.ca/shellfish-mollusques/index-eng.htm

USA

Connecticut: www.ct.gov/doag/cwp/view.asp?a=1369&q=259178

Delaware: www.dnrec.delaware.gov/wr/Services/OtherServices/Pages/RedTideInformation.aspx

Florida: myfwc.com/REDTIDESTATUS

Maine: www.maine.gov/dmr/rm/public_health/closures/shellfishhotline.htm

Massachusetts: www.mass.gov/dfwele/dmf/recreationalfishing/rec_index.htm#shellfish

New Hampshire: 1-800-43CLAMS; www.wildlife.state.nh.us/marine/redtide.html

New Jersey: www.state.nj.us/dep/fgw/saltwater.htm

New York: 631-444-0480; www.dec.ny.gov/outdoor/345.html

North Carolina: www.ncfisheries.net/recreational/recguide.html

Rhode Island: www.dem.ri.gov/topics/mftopics.htm

South Carolina: www.dnr.state.sc.us/marine/shellfish/regs.html

Virginia: www.vdh.state.va.us/shellfish/index.asp

HOW TO USE THIS GUIDE

This book identifies the common animals and plants, including color photographs of the organisms, that you’ll see along the Atlantic Coast, and contains important information that will help you identify each species. This next section highlights the criteria used under each heading to help in the identification of each organism.

PHYLUM

This classification comprises a very large group of living organisms, which are often divided further into many classes. For example, both humans and fish belong to the phylum Chordata, because both species have vertebrae, and both snails and clams belong to the phylum Mollusca because they share one or more internal or external shells, a muscular foot, and an unsegmented body with a mantle or fold in the body wall.

CLASS/FAMILY

The class or family is a grouping of one or more genera (see Species Names below) with similar overall characteristics. All oysters, for instance, belong to the oyster family (Ostreidae), which includes several genera.

SPECIES NAMES

A common name and scientific name are presented for each species. Every living organism has a unique scientific name consisting of two parts: the genus or genera (plural) and the species. Scientific names change occasionally as new information is discovered. This book contains the most current names. Common names are those used in everyday conversation by people who live in an area where the species occur, so many organisms have several common names.

AUTHORITY

This is the individual who has provided the initial account published for this particular species.

OTHER NAMES

Any additional common or scientific names known for the species are included here.

DESCRIPTION

This section provides the distinguishing physical features and behavior required in identifying the species.

SIZE

This section includes dimension(s) of the largest individuals or colonies commonly found; younger individuals are normally smaller.

HABITAT/ECOLOGY

The type of area where the species lives is provided, which is often helpful in making an identification.

GEOGRAPHIC RANGE

This section describes generally the area of the Atlantic where the species is found, as well as other countries or continents where this species resides or was introduced.

NOTES

This section provides further information of interest, usually relating to the natural history of the species or perhaps ways in which it is used by humans for food or other purposes.

SIMILAR SPECIES

If there are look-alike species that often create difficulties in the identification of that species, these are treated in the relevant species account at the end (or cross-referenced).

INTRODUCED SPECIES

IIntroduced species are noted with a symbol that indicates that this species is not native to this area. This alien species has been introduced by accident or for a specific purpose by man.

Sponges

(Phylum Porifera)

Sponges are the simplest of marine organisms and in fact do not have specialized body tissues. Sponges have an internal skeleton that is made up of microscopic spicules (rods) that are comprised of either calcium or silicon. This gives them their shape and each species has their own type of spicule which is used to identify individual species.

Water circulates through the body by entering the body via minute pores called ostia (singular, ostium) and leaves through large pores called oscula (singular, osculum). Flagella (microscopic whip-like structures) pump water through a system of canals, which circulate the water within the sponge by their continual beating. Both food and oxygen accompany the water so that the sponge is able to feed and breath with this system. Body wastes exit the oscula along with the water. Sponges attach to solid objects such as rocks and so do not move around. They often grow best where water currents are the greatest.

Eyed Finger Sponge

Haliclona oculata

Authority: (Linnaeus, 1759)

Other Names: Also known as dead man’s fingers, eyed sponge, finger sponge; formerly classified as Chalina oculata

Description: Color varies widely from tan to grayish brown, occasionally purple, rose, or reddish orange. The shape of this species varies with the number of its branches and their size. Its stalk is narrow, supporting several branches. Its pores (larger openings that allow water to exit the cavity) are large enough to be noticeable and scattered over its surface. Branches are generally flat but noticeably rounder south of Cape Cod.

Size: Height to 17.5 (450 mm); thickness to 0.5 (12 mm)

Habitat/Ecology: Attached to rocks; low intertidal zone to water 400' (124 m) deep

Geographic Range: Labrador to North Carolina

Notes: This species is often found washed ashore after a storm. Fresh specimens will often have much more color than older, sun-bleached individuals. This northern species is frequently found stranded on our shores. To identify many species of sponges, you need to look at the spicules with a microscope. This species, however, is easy to identify without a microscope.

Similar Species: Common Palmate Sponge (Isodictya palmata) is a smaller species, to 12" (30 cm) high, with conspicuous pores on the flat sides of the erect, flattened branches. Its color ranges from yellowish to light brown or red-brown. This subtidal species ranges from Nova Scotia to North Carolina and is sometimes found washed up on the shore.

Northern Palmate Sponge (Isodictya deichmannae) is very similar to the common palmate sponge but requires a microscope to identify it with certainty. It ranges from Newfoundland to Rhode Island.

Purple Encrusting Sponge

Haliclona cinerea

Authority: (Grant, 1826)

Other Names: Also known as purple sponge, volcano sponge; formerly classified as Haliclona permollis

Description: Its coloration ranges from pink to lavender or purple. Its surface is smooth and soft. Its volcano-like oscula may reach 0.25" (6.5 mm) on raised tubes.

Size: To 36 (91 cm) wide; 1.6 (4.1 cm) high

Habitat/Ecology: In protected waters, encrusted on rocks, in tidepools, and on floating docks; low intertidal zone to water 20' (6 m) deep

Geographic Range: New Brunswick to lower Chesapeake Bay; Washington to California

Notes: The wonderful color of this common sponge makes it easy to identify. It is also found in the Pacific Northwest where it lives higher up on the shoreline. Some authorities speculate that there may be more than one species present.

Bread Crumb Sponge

Halichondria panicea

Authority: (Pallas, 1766)

Other Names: Also known as crumb of bread sponge, crumb-of-bread sponge

Description: Two color forms are common—yellow and pale green. The texture of this species is firm, compressible, and easily torn. Oscules are regularly spaced at the tips of volcano-like mounds.

Size: Greater than 12 (30 cm) wide; 2 (5.1 cm) high

Habitat/Ecology: On exposed shores and in quiet bays, attached to rocks, wharves, pilings, and in tidepools; low intertidal zone to water greater than 1650' (500 m) deep

Geographic Range: Arctic to Cape Cod; Alaska to California

Notes: The crumb of bread sponge gets its common name from its scientific name, panicea, which means made of bread, referring to its texture and the ease with which it breaks apart. This species has been called the most common intertidal sponge of our Atlantic Coast.

The green color is caused by symbionic microscopic algae called Zoochlorellae that live in sponge colonies. This sponge receives nutrients produced from the algae, and the algae receive shelter from the sponge. It’s truly amazing that this intertidal sponge can also live at depths greater than 1650' (500 m) deep!

Bowerbank’s Halichondria

Halichondria bowerbanki

Authority: (Burton, 1930)

Other Names: Also known as Bowerbank’s crumb of bread sponge, bread sponge, crumb-of-bread sponge, yellow sun sponge

Description: Color ranges from yellowish to orange-brown or olive-green. This species is soft, with tissue that tears easily. It typically has a very irregular shape, and its surface is often raised in leaflike masses. This species forms somewhat thicker sponges than the new colonies of other sponges.

Size: To 6 (15 cm) across; 3 (7.5 cm) high

Habitat/Ecology: On sheltered shores, estuaries, lagoons, and in tidepools; usually in indirect light on pilings, rocks, shells, and seaweeds; low intertidal zone to shallow subtidal depths

Geographic Range: Bay of Fundy to Cape Hatteras

Notes: In May and early June, this common fouling sponge is most visible, but by late June and early July, it disappears for much of the summer. By late September, however, new colonies begin again, and soon afterward they may be found on rocks and shells.

If you look under the microscope at the spicules, they look like needles with one pointed end and one rounded end. This species can be difficult to separate from the sun sponge in the field.

Similar Species: Sun Sponge (Hymeniacidon heliophila) (see p. 5) is a southern species ranging from Cape Cod to Gulf of Mexico that is found in sites that receive direct sunlight. It is yellowish and grows to the same size as Bowerbank’s halichondria. Looking under the microscope at this species, you will observe its spicules that resemble needles with two pointed ends.

Loosanoff’s Haliclona (Haliclona loosanoffi) forms dark tan to gold crusts, with oscules on the chimneys that can grow to 1 (2.5 cm) high. Each sponge may reach 3 (7.5 cm) across, but several often fuse together to form large mats.

Sulfur Sponge

Aplysilla longispina

Authority: (George and Wilson, 1919)

Other Names: Also known as yellow sulfur sponge; formerly included with Aplysilla sulfurea

Description: Healthy sponges of this species have a distinctive yellow color; however, this color changes dramatically to purple on injured or dead individuals. This encrusting species has a soft consistency, with a glossy, lacquered look out of water. It also displays pointed projections arising from its upper surface, with no pores visible.

Size: To 8 (20 cm) in diameter; 0.8 (0.5 cm) in thickness

Habitat/Ecology: Encrusts rocks, wrecks, shells, and other sponges; low intertidal zone to water 82.5' (25 m) deep

Geographic Range: North Carolina to Florida, Caribbean, and West Indies

Notes: This sponge lacks the silica or calcium carbonate that is found in the skeleton of most sponges. Instead, thick, tough fibers of the protein spongin support this species and give it form. This characteristic is true for all members of the genus Aplysilla.

This species was formerly considered to be the same species as European sulfur sponge, Aplysilla sulfurea. New research has determined that the European sulfur sponge is from the Adriatic Sea and the western Mediterranean, and it is a separate species that is restricted to that area.

Sun Sponge

Hymeniacidon heliophila

Authority: de Parker, 1910

Other Names: Formerly classified as Stylotella heliophila, Stylotella simplissima

Description: Specimens living in sunlit areas are light yellow overall with a tint of olive green. In shady sites, however, they are often a bright orange to reddish orange. This species forms encrusting sheets with numerous erect, irregular, chimney projections. Large specimens are normally soft and easily torn, but small specimens are stiff and fleshy.

Size: Can exceed 16 (40 cm) across; to 1.5 (4 cm) high

Habitat/Ecology: On shells, sand flats, pilings, and rock jetties; low intertidal zone to subtidal depths

Geographic Range: North Carolina to the Caribbean

Notes: This species is one that can tolerate being exposed to direct sunlight and air. Its color pigmentation helps to protect it from becoming sunburnt. Specimens that have been found living in deeper waters appear not to produce chimney projections, likely due to currents in the ocean.

Redbeard Sponge

Clathria prolifera

Authority: (Ellis and Solander, 1786)

Other Name: Formerly classified as Microciona prolifera

Description: Red to orange in color. It grows with a distinctive, knobby, multi branched shape. Oscula are inconspicuous and scattered over the surface.

Size: To 8 (20 cm) or more high; 8 (20 cm) wide

Habitat/Ecology: In protected bays and estuaries; on rocks, pilings, shells, and other hard objects; low intertidal zone to shallow subtidal waters

Geographic Range: Prince Edward Island to Texas

Notes: This species is often found on the beach washed up after a storm. Individuals start out as small encrusting sponges that develop small lobes. As the sponge grows, the lobes mature into branches. The redbeard sponge is known for its ability to withstand pollution and the low salinities within bays and estuaries.

Club-finger Sponge

Desmapsamma anchorata

Authority: (Carter, 1882)

Other Names: Also known as lumpy club finger sponge, overgrowing sponge; formerly classified as Fibularia anchorata

Description: Variably colored from purplish pink to salmon-pink. Produces upright branches that divide dichotomously with swollen processes. The oscules are abundant and visible on its branches, and this sponge’s consistency is soft and compressible.

Size: To 14 (35 cm) high or more; to 6 (15 cm) in diameter

Habitat/Ecology: On stones, mangrove roots, and similar objects in sandy areas of shallow reefs and lagoons; subtidal depths to water 132' (40 m) deep

Geographic Range: North Carolina to Florida and the Caribbean; northwestern Europe and Africa

Notes: The club-finger sponge, like many other species, changes color because it oxidizes out of water. This species turns to black or dark brown. The skeleton of this species is greatly influenced by the quantity of foreign material, including sand, which is incorporated into the structure of the sponge. The club-finger sponge is often found washed up on our shorelines.

Sheepswool Sponge

Hippospongia lachne

Authority: (de Laubenfels, 1936)

Other Name: Also known as sheep’s wool sponge

Description: Color ranges considerably from olive to black. Its shape is round, with an irregular surface and large, raised pores.

Size: Width to 36 (91 cm); height to 24 (61 cm)

Habitat/Ecology: On rocky bottoms; subtidal waters to 150' (46 m) deep

Geographic Range: Florida to Mexico; Bahamas; West Indies

Notes: Like several other sponge species, this one is only found if it is washed ashore after a storm. This massive species has long been the focus of a major commercial sponge industry. At one time sponge diving was the way large numbers of sponges were harvested in Florida. Today natural sponges have been largely replaced with synthetic sponges. Tourists now purchase natural sponges as souvenirs. Fragments of this species are sometimes found washed up on the shore.

Brown Finger Sponge

Axinella pomponiae

Authority: van Soest and Rützler, 1998

Other Name: Formerly classified as Homaxinella rudis

Description: Color varies from dark purplish red to reddish brown. The branches are erect, flexible, and tapering with occasional lumps. The branches also commonly fuse together and are sometimes dichotomous at the tips.

Size: To 12 (30 cm) high; branches to 0.75 (2 cm) across

Habitat/Ecology: In sandy areas with hard bottoms near reefs; subtidal waters to 165' (50 m) deep

Geographic Range: North Carolina to Caribbean, Gulf of Mexico

Notes: Like many other sponges, this subtidal species is often found washed up on the shore. This species is very soft in consistency.

Yellow Boring Sponge

Cliona celata

Authority: Grant, 1826

Other Names: Also known as yellow sulfur sponge, sulfur sponge, boring sponge

Description: A yellowish body protrudes from holes in mollusk shells or coral.

Size: Diameter to 0.1 (3 mm); height to 0.1 (2 mm)

Habitat/Ecology: On shells, coral, and occasionally concrete; low intertidal zone to water 132' (40 m) deep

Geographic Range: Gulf of St. Lawrence to Gulf of Mexico; Washington to California

Notes: The larvae of this remarkable sponge settle on calcareous shells and coral, where they secrete sulfuric acid, creating pits and galleries in the shells. This removes excess shells from the ocean that could otherwise overwhelm the ocean bottom.

This sponge is recognized as a pest in oyster beds. Since it simply weakens the shells of the oyster, it is not a parasite, but in severe attacks it can exhaust and even kill its host. You may also encounter additional boring sponges, such as the red boring sponge (below).

Similar Species: Red Boring Sponge (C. delitrix) is orange-red in color. This species of sponge has been known to kill corals.

Cnidarians

(Phylum Cnidaria)

The phylum Cnidaria is made up of three classes of organisms that appear to be quite different from each other: sea anemones (Anthozoa), hydroids (Hydrozoa), and jellies (Scyphozoa).

All cnidarians produce their own nematocysts. These nematocytsts, however, vary greatly in their function. Some are sticky to capture prey, while others use small amounts of poison, and still others use them to lasso their prey. In fact, seventeen different types of nematocysts have been described. Most cnidarians are radially symmetrical, with their parts arranged around the center like the petals of a daisy. Only one opening is present: the mouth. It opens to their gastrovascular cavity. The mouth is surrounded by several tentacles to capture food. Wastes also exit through the same opening.

Members of this phylum are present in two forms. The polyp is the first form, which is represented by the sea anemone. Polyps are stationary, since they are attached to a substrate. The second form is the medusa, which is commonly found in the jellies. Medusae move by opening and closing, forcing water in and out, which moves the jelly in the opposite direction.

While some cnidarians are only present as a polyp or a medusa, many have alternating generations. This means that their life cycle includes both polyp and medusa generations.

CORALS AND SEA ANEMONES (Class Anthozoa)

Sea anemones are soft-bodied organisms that possess unbranched tentacles around their mouth used to obtain food. Reproduction is normally sexual, but some species reproduce asexually. Although sea anemones appear to be sedentary, they actually can glide about surfaces slowly on their pedal disks. You’ll find two types of coral: soft and hard. Soft corals (octocorals) may be shaped like fans, bushes, or rods. Their polyps are present in scattered cups. The outer covering to their flexible fingers consists of a mesh-like calcium structure that surrounds an inner core of flexible protein called gorgonin. Hard corals (stony corals) on the other hand are colony based so that when one feeds, all nearby polyps benefit. Each individual in these colonies secretes calcium carbonate in the shape of a cup to form a solid structure that is characteristic for the species. Polyps are best viewed at night when they stretch to their full length to feed. During the daytime, they remain retracted and are difficult to see.

SOFT CORALS

Brilliant Sea Fingers

Titanideum frauenfeldii

Authority: (Kölliker, 1865)

Other Names: Also known as orange bush coral; formerly classified as Solanderia frauenfeldii

Description: Color varies from yellow to deep red. The colonies consist of stiff, cylindrical, rod-like, tapering branches. They are unbranched when small or moderately branched when larger.

Size: Height to 15 (38 cm); branches to 0.33 (.8 cm)

Habitat/Ecology: On sand-covered limestone; subtidal depths 60–100' (18–30 m)

Geographic Range: North Carolina to Cuba; northern Gulf of Mexico

Notes: This bushy soft coral is a deep-water species that attaches itself to hard surfaces with a holdfast. It has no wood-like stem like the related sea fans and sea whips do. It is commonly found stranded on the beach after storms.

Sea Whip

Leptogorgia virgulata

Authority: (Lamarck, 1815)

Other Name: Also known as colorful sea whip

Description: Color varies widely, purple to yellow or orange, tan, white, and red. It has cylindrical stems—slender, whip-like, and sparsely branched close to the base, with small pores.

Size: Height to 36 (90 cm); stems to 0.5 (1.3 cm) wide

Habitat/Ecology: Attaches to rocks, shells, as well as on floating docks, rock jetties, and oyster reefs; shallow subtidal depths to 100' (30 m) deep

Geographic Range: New Jersey to Florida; more common south of Cape Hatteras

Notes: This coral, like all soft corals, is comprised of colonies of tiny polyps, each with eight tentacles (hence the name octocoral). A tough outer rind and horny core are the basis for the flexibility of this species.

Several organisms are often found living on this coral. The Atlantic wing-oyster, Pteria colymbus (see p. 151), is one that frequently attaches to a branch. The sea whip barnacle, Conopea galeata (see p. 206), lives on this species exclusively, where it is very often overgrown by host tissue. Another species, the single-toothed simnia, Simnialena uniplicata (see p. 91), may also be found as it clings to a branch. Since it feeds on the host, it actually incorporates the pigment of its host into its shell.

The sea whip has inhibitors that help to protect it from the sea whip barnacle and a variety of bryozoans that try colonizing on this species’ branches. These inhibitors, however, are not always successful.

Similar Species: Straight Sea Whip (Leptogorgia setacea) is a similar species except that it is unbranched. It’s common from the Chesapeake Bay to Brazil, and its colors are also similar to the sea whip. It grows to 6' (183 cm) high. Cups are found crowded and irregularly spaced in two rows. Often grows unattached.

Regal Sea Fan

Leptogorgia hebes

Authority: Verrill, 1869

Other Names: Also known as false sea fan; formerly classified as Lophogorgia hebes

Description: Color ranges from red to purple or orange and dark yellow. This species is highly branched, with dome-like mounds and slit-like pores on somewhat flattened stems.

Size: Height to 18 (45 cm); stems to 0.25 (.6 cm) in diameter

Habitat/Ecology: On hardbottom; subtidal to waters 89' (27 m) deep

Geographic Range: Virginia to northern Florida and Gulf of Mexico to Aruba and Brazil

Notes: This coral attaches to hard substrates by a holdfast. Research in the Gulf of Mexico showed that this species begins to spawn in late August or early September. Sea fans can be aged just like trees—by counting the annual rings. Females begin their reproduction at two years of age while males do not begin until six years old. Interestingly, the sex ratio in the Gulf of Mexico favored females 2:1.

Common Sea Pansy

Renilla reniformis

Authority: (Pallas, 1766)

Other Name: Also known as sea pansy

Description: The color of the heart-shaped frond is rose or pale purple, with white and yellow polyps on the dorsal surface. The stalk is purple and about the same length as the diameter of the frond.

Size: Frond to 1.5 (40 mm) wide; total length with stalk to 3 (75 mm)

Habitat/Ecology: It anchors itself in soft sand; low intertidal zone to water 360' (108 m) or more deep

Geographic Range: Cape Hatteras to Brazil, Caribbean

Notes: The common sea pansy uses its anchoring stem to keep it in place. It is capable of repositioning itself if it becomes covered with sand. It can also free itself from its location by extending and contracting its muscular stem. The yellow polyps on the frond are the feeding polyps that capture food. The white polyps are used as water pumps that can expand the body when it is deflated.

If the common sea pansy is disturbed, it emits a strong bioluminescent light that is only visible at night. One stimulus that evokes bioluminescence is the presence of a striped sea slug called the tiger armina (Armina tigrina), which is a predator of the common sea pansy.

HARD CORALS

Northern Star Coral

Astrangia poculata

Authority: (Ellis and Solander, 1786)

Other Names: Also known as star coral, northern stony coral; formerly classified as A. astreiformis, A. danae

Description: Normally white or pink, the northern star coral turns brownish when symbiotic algae are especially abundant inside its tissues. It forms encrusting masses with a distinctive star-like pattern.

Size: Colony diameter up to 12 (30 cm), but normally to 5 (12.7 cm)

Habitat/Ecology: On rocks and other hard surfaces; subtidal depths to 130' (28 m)

Geographic Range: Cape Cod to Florida

Notes: This encrusting stony coral does not form reefs but forms compact colonies instead. This subtidal species is often found washed up on the shore. Symbiotic algae (Zooxanthellae) are present within this stony coral, and as a result, they are able to survive in deeper waters with less light requirements than soft corals. Minute white bumps found on the surface are clusters of stinging capsules that are used to capture prey.

Compact Ivory Bush Coral

Oculina arbuscula

Authority: Agassiz, 1864

Other Names: Also known as compact ivory tree coral, ivory bush coral

Description: Color is normally white on the beach after being bleached by the sun. In life, the colonies range from tan to dark brown. This species has finger-or pencil-shaped branches with many cups.

Size: Colonies occasionally reach up to 3' (1 m) but are normally